"<!-- InstanceBeginEditable name="EditRegion2" -->"
"<!-- InstanceEndEditable -->"
When I create a page whatever is in that Region gets fed into the new page.
That is correct - it's what SHOULD happen, since you are creating this page de novo. The new page is filled with ALL of the content on the template page.
Thereafter, any changes don't feed through.
Any advice appreciated. Thanks
Thats correct too! Changes to content in an editable region of a template DO NOT AFFECT ANY CONTENT ON THE CHILD PAGES. If it did, then you could never have any unique content on any page.